Twisting machine



@fc-, 21946?. Q. WENNBERG 292179301 Twls'rme MACHINE Filed April 18, 1939 5 Sheets-Sheet 2 /6 INVENTOR 00D Wav/V559@ ATTORNEY @ci 8, 1949. o. WENNBERG TWISTING MACHINE 5 Sheets-Sheet 3 lFiled April 18. 1939 Oct. 8, 1940. o, WENNBERG TWISTING MACHINE Filed April 18, 1939 5 Shmats-Sheat 4 ATTORNEY O. WENNBERG TWISTING MACHINE Oct. 8, 1940.

ATTORNEY Patented Oct. 8, 1940 UNITED rs'rares 'site 26 Claims.

The invention relatesv to machines for twisting metallic bars or rods and more particularly for helically twisting two adjacent steel bars or' rods together for use in concrete reinforcement and .i the like.l he object ofthe invention is to provide a machine of simple' construction whereby the twisting of the bars or rods will b-e effected with maximum efficiency; The. invention contemplates particularly the provision of novel mechanism in which the twisting operation is automatically controlled in accordance'with predetermined requirements, and whereby a definite controlled recoil-ing operation'. is eiect'ed' at the end of the twisting operation. Other more specinc objects will appear from the description hereinafter and the features of novelty will be pointed out in the claims.

In the accompanying drawings,Y which illustrate an example of the invention without dening its limits, Fig. I isa plan View of the novel twisting machine; Fig. 2 is an enlarged vcrosssection thereof.` on the line 2 2' of Fig.` 1;' Fig. 3 is a similar view on. thel'ine 3 3 of Fig. l; Fig. 4 illustrates the helically twisted bars or' rods as 25 produced by the novelV4 machine; Figs. 5 and 5aL are diagrammatic viewsv which together show the complete layout; Fig. 6 is an enlargedv detail section of a control valve' which is utilized at various rpoints in the machine; Fig. 7 is a horizontal section on the line T T of Fig. 2; Fig. 8 is a fragmentary detail view illustrating clamping devices forming part of the machine; Fig. 9 is a detail section ofthe gripping jaws forming part' of said clamping devices; Fig. 10 is a face View of one tional View illustrating a control valve embodied in the machine at several points thereof.

As shown in the drawings, the machine' comprises a supporting base |5 mounted upon beams It or the like, said base |'5 being of rectangular oblong shape as illustrated in Fig. l, and of any suitabledimensicns. At an intermediate point, the base i5 carries a preferably circular casing Il xed in place in any convenient manner and provided with a radially open slot I8 and having circular axially registering openings i9 in its opposite walls eccentrically located with respect to the casing l1 as sho-wn in Fig. 2L A plurality of bearing rollers 2Q are arranged' in opposed groups about the openings I9, and are rotatably mounted upon opposite' walls ofl said casing il so as tol project toward each other as illustrated in Fig. 7; in the preferred arrangement the axes of the rollers 2Q are inclined relatively to the casing walls on which said rollers are journalled,

' of said gripping jaws, andl Fig. 11 is a detail sec-v (Cl. Mil-149) the axes of the rollers 2li in the two respective groups converging toward each other as shown in' Fig. '7. v

An annular member 2i is rotatably supported on the rollers il and is provided with an outwardly projecting radial web 22 formingpart of or secured to a toothed gear 23,"and an inwardly directed web 24 terminating in a hub 25 located in concentric relation to the member 2 l. An outwardly open radial slot il@ extends from the'periphery of the gear' 23 to the axial bore of the hub 25 and is adapted to register with the radially open slot I8 of the casing l'l for the purpose to be more fully set forth hereinafter. A twisting head or bushing 2l is mounted'in the axial bore of the hub 2S and forms part of' an annular iiang'e 28 which lies in: surface engagement with the hub 25 for the accommodation of screws 29 whereby said bushing 2l is xed interiorly of the hub 25. Thel bushing 2f? and flange 28 include' a common recess' orseat 3B' having its closed bottom in registry withthe aXis'of the bushing 2l and communicating with the outwardly open radial slot 2&5; the flange Etlincludes an outwardly flaring open' slot 3i which leads to the recess or seat as shown in Fig. 2.

The machine further includes carriers or troughs 32 located in spaced longitudinal alignment and extending in opposite directions upon opposite sides of the casing' Il as shown in Fig. 2. The carriers or troughs t'are supported upon rollers 33 jo'urnalleclv in bearings 34 fixed thereon, said rollers 35iv being arranged to traverse horizontal "tracks 35 located at spaced intervals lengthwise of the machine as illustrated in Fig. 1. The tracks 35 are carried by brackets 35 mounted upon the supporting 'base it, the arrangement being such that the bottoms of the carriers or troughs 32 are located Aapproximately at the level of the recess or seatl 3d of the twisting head or bushing 2l when the latter occupies the normal position shown in Fig. 2. AAt spacedintervals, preferably in contiguous relation to the brackets 36, the carriers or 'troughs 32 are'connected with the upper runs of sprocket chains 3l or their equivalent; the latter pass over sprocketwheels 38 or the like rotatably mounted on the brackets 3,6, and over sprocket wheels 39 or the like fixed upon a shaft 4&3 extending lengthwise of the machine as illustrated in Fig. l,y and journalledv in bearings 4l on the brackets 3E, as shown in Fig. 3. yDuring an operative period of the machine, the shaft l0 is rocked on its axisftc correspondingly actuate the sprocket chains 3l ortheir equivalentV to thereby intermittently recprocatelthe s the like, with a sprocket Wheel 44 rotatably mounted on one of the supporting brackets 36. -A connecting rod or pitman 45 has its one end pivotally connected at 46 with the face of the sprocket wheel 44, and its other end pivotally connected at. 41 with a crank 48; the latter is l carried by or forms part of the shaft 49 of an electric motor 50 or equivalent source of power mounted upon the base I5 as illustrated in Figs.

1 and 3.

The outer ends of the carriers or troughs 32 are movable into co-operativ-e relation to clamping means located in spaced relation to the`cas` ing I1 upon yopposite sides thereof, whereby the opposite` end portions of the `bars or rods'are grippedfand clamped against movement during the twisting operation as will be more fully described hereinafter. `The clamping means, in its illustrated form, consists of stationary jaws or clamps 5| suitably mounted in the machine, as for instance, upon brackets 52 supported upon theibeams I6 which project beyond the base I5 at opposite ends for this purpose. The aforesaid clamping means further includes .movable jaws or clamps 53 slidably vmounted for vertical movement in guides 54 forming part'of or supported by auxiliary frames 56 suitably xed upon the beams I6. As shown in Figs. 8, 9 and 1.0, the jaws 5| and 53 are preferably provided in the end or active faces with recesses in which.

clamping blocks 5|a and 53a of predetermined metal are respectively fitted and secured in any convenient manner. The active clamping surfaces of the blocks 5|a and 53a preferably are countersunk in the respective recesses and are v transversely curved as illustrated in Fig. 8; in

addition said surfaces are preferably provided with teeth 5|b and53b respectively, said teeth extending yin the direction of the transverse curves andv preferably tapering outwardly in cross-section to sharp gripping edges as shown in Fig. 9.' The jaws or clamps 53 are carried by plungers 51 depending from pistons 58 slidlable in cylinders 59 carried by the frames56,

the cylinders 59 having upper ports 60 and lowerr ports 6| respectively connected by means of pipes or conduits 62 and 63 with upper and `lower ports 64 and 65 respectively of valve cylinders` 66 in which piston valves 58 of conventional type are slidable. The cylinders 66 furtherinclude intermediateports 61 which are connected by means of pipes 68 with iiuid pressure pumps 69 of suitable type operated in any convenient manner 'and preferably by means of electric motors 10 fixed upon the frames 56; in

`the preferred arrangement relief valves p 1| of suitable and conventional type are interposed in the pipes 68 between the cylinders 66 and pumps 69. The valves in the cylinders 66 are operated andcontroll-ed by solenoids 12 which themselves are electrically controlled in thev manner to be more fully set forth hereinafter.

The previously mentioned toothed gear 23 in `the casing 1 is interrupted by the radial slot 26, and meshes with pinions 13 and 14 journalled in the casing I1 at points respectively above and below the horizontal'plane in which the axial center of the gear 23 is located. The pinions 13and 14 vboth mesh with a pinion 15 carried by la shaft 16 rotatably mounted in the casing I1 in horizontal registry with the axial center of the gear 23. The shaft 16 carries an additional pinion 11 which meshes with a driving pinionv 18 mounted within the casing |1 upon the power shaft 19 of the hydraulic motor 80 of a conventional hydraulic transmission of constant horsepower and variable lspeed and including a conventional oill tank 8|; the aforesaid hydraulic transmission may be of any well-known type as exemplified for instance bythe so-called Vickers hydraulic transmission. As the latter is well-known and as the hydraulic transmission per se forms no part of the invention, vit has been deemed .sufficient to illustrate the same diagrammatically as in Fig. 5. As shown in Figs. 1 and 5, the shaft 19 may also carry a fly wheel 82, the latter being located between the casing I1 and the hydraulic motor 86 in the illustrated example. The hydraulic transmission further includes the customary hydraulic pump 83, having its driving shaft 84l operatively connected with a suitable driving means, such as the shaft 65 of an electric motor 86. v

The hydraulic pump 83 is connected by means of pipes 81 and 88 with the hydraulic motor 80, the speed of which is controlled by the cusrelatively' torsaid casing` 8|- as shown in Fig. 5. A by-pass relief valve 93 is interposed in the pipe 81 and is connected byr means of a by-pass Apipe 94 with the pipe 88;Ya similar by-pass relief valve 95 is located in the pipe 88 and is connected by means of a lpipe 96 with the pipe 81.

Thehydraulic pump 83 is controlled by a conventional tilting box 91 and associated elements in the well-known way, said tiltingfbox 91 being connected by means of a link 98 with a plunger 99 slidablymounted in a cylinder |00; a suitable stop may be providedfor arrestingthe adjustment of the tilting box 91 in one direction.

The one end of the cylinder |00 is connected by means of a pipe |02 with a port |03 of a valve casing |04 located within the tank 8|, and the opposite end of said cylinder communi- .cates with a pipe.| leading to a port |06 of The latter is provided.`

saidH valve casing |94.

with an additional port |01 which connects with a tube |08 open to theinterior of the tank 8|.

.A further port |09 with which said casing |04 is provided communicatesfwith a pipe ||0 leading to an auxiliary pump operatively coupled to the shaft of the electric motor 86; the inlet side of the pump is connected by means of a pipe ||2 with the interior of the tank 8|.v

An -auxiliary relief valve I3 is interposed in the pipe ||0 and is provided with a pipe ||4 communicating with the tank 8|. A supercharging line |I5 communicates through the relief valve 93 with the pipe 81 and leads to the pipe ||0 at a point ahead ofthe auxiliary relief valve H3, and a similar supercharging line I|6 communicates through the relief valve with the `pipe 8,8, and is also connected with said supercharging line |I5;l check valves,||1 and ||8 are llocated in the line ||5 and line |I6 respectively as illustrated diagrammatically irl-Fig. 5. The supercharging lines ||5 and ||6 being connected through the pipe H0 with the auxiliary pump serve to keep the pipes 8.1 and 88 filled withA oil at all times.

The by-pass relief valves 93 and 95 are further connected by means of a bleeder pipe ||9 and a bleeder branch |20 with a port |2| of a valve casing |22 located in the tank 8|, said valve casing |22 having additional ports |23 connected with tubes |24 open to the interior of said tank 8|.

In the illustrated example of the novel machine, the pinion 11 in the casing |1 is connected by means of gearing |25 located within a gear reduction box |26 mounted on the casing I1, with a shaft |21 journalled in said gear box |26 and carrying an index disc |28 exteriorly thereof. The index disc |28 is provided. at a predetermined point on its surface with at least one opening or recess |29 for the accommodation oi a slidably mounted index pin |30 controlled by and constituting an extension of a stem |3| forming part of a piston |32 as shown diagrammatically in Fig. 5. The piston |32 is slidable in a cylinder |33 mounted for instance upon the gear reduction box |26 and having ports at its opposite ends in communication respectively with conduits or pipes |34 and |35 which lead into the oil tank 8| as illustrated in Fig. 5.

The pipe |34 communicates with a port I 36 of a valve casing |31 located within the tank 8l, while the pipe |35 is connected with a second port |38 of said valve casing |31 as shown in Fig. 5. Another port |39 of said valve casing |31 communicates with a tube |40 open to the interior of the tank 8|. and stillanother port |44 of the valve casing |31 is connected by means of a pipe |42 with the pipe I0 leading to the previously mentioned auxiliary fluid pump The interior arrangement of the valve casing I 31 and its associated parts is shown in Fig. 6 and includes an internal chamber |43 communicating with the port |38 and with annular internal channels |44 and |45. The port |36 communicates with an internal chamber |46 which in turn leads to annular internal channels |41 and |48, while the port |4| is connected with an annular internal channel |49. An internal channel |50 connects the annular channels |44 and |48 and communicates a'lso with the port |39 of the casing |31. The latter further includes axial openings 5| and |52 whereby communication between the port |4| and the ports |36 and |38 respectively is established and additional corresponding axial openings in which piston valves |53 and |54 are slidably guided; the piston valves |53 and |54 are connected with each other by a neck |55 of relatively reduced diameter. The valves |53, |54 and the connecting neck |55 are carried by a valve stem |56 slidably mounted in one end of the casing |31 and projecting exteriorly thereof', a coil spring |51 serving to yieldingly maintain the piston valves |53 and |54 with the connecting neck |55 in the position illustrated in Fig. 6, and to return said valves and neck thereto. For the purpose of controlling and operating the valves |53 and |54 with the neck |55, the valve stem |56 is operatively connected with a solenoid |58 mounted on the tank 8|.

The valves in the valve casings |04 and |22 correspond in construction and arrangement to the aforesaid valve in the valve casing |31 and likewise are operatively connected respectively with solenoids |59 and |69 also fixed upon the tank 8| The previously mentioned by-pass relief valves 93 and 95 may be of any conventional type constructed for instance as illustrated in Fig. 11 which shows the valve 93, it being understood that the valve is of similar construction and arrangement. As indicated in Fig. 11, the pipe 94 leads to a port |6| which is provided at its inner end with a valve seat |62, while the pipe 81 is connected with the interior chamber |63 at opposite sides of the valve casing. A pressure valve |64 normally rests upon the seat |62 and is yieldingly maintained in place thereon by a spring |65 to control the communication between the pipe 81 and the by-pass pipe 94, said valve |64 being slidably fitted in an internal recess |66 as shown in Fig. 11. The arrangement is such that the valve |64 permits communication through the interior chamber |63 between the sections of the pipe 81 at al1 times. A vent |61 extends through the valve |64 and establishes communication between opposite sides thereof, that is between the charnber |63 and that part of the recess |66 which is above said valve |64; a .second vent |68 extends through the latter in registry with its major axis as illustrated in Fig. 11. The vent pipe ||9 leads to a channel |69 in the casing of the valve 93, which channel |69 in tur-n communicates with the recess |66 above said valve |64. A check valve |10 acted on by a spring |1| controls communication between a channel |12 leading to the recess |66 above the Valve |64, and a channel |13 leading to the port |6| below said valve; the pressure exerted by the spring |1| on the valve |10 and consequently the resistance of the latter to developed pressure may be regulated by an externally accessible adjusting screw |14 against which one end of said spring |1| abuts as shown in Fig. 11. It will be understood that the description of the internal construction and arrangement of the by-pass relief valve 93 applies also to the by-pass relief valve 95.

The power shaft y19 of the hydraulic motor 80 is operatively connected with a suitable counter 15 operating in the conventional manner to count revolutions of the shaft 19 and of the twisting head or bushing 21 for the purpose to be more fully described hereinafter. The counter E15 in turn is connected by means of a one-way clutch |16 with a second counter |11 which also is arranged to count revolutions of the shaft 19 and twisting head 21 b-ut in a reverse direction for the purpose to be more fully set forth hereinafter. Both counters |15 and |11 include resetting levers |19 which, as shown in Fig. 5, may be connected with an operating rod |19 for concurrent operation to manually or otherwise reset said counters to Zero or some other predetermined point. It will be understood that the counters and |11 are arranged to open and close electric circuits at predetermined points in their operation as will appear more fully hereinafter.

The machine further includes pressure operated switches |80 of any conventional type connected by means of pipes |3| with the conduits 63 as illustrated diagrammatically in Fig. 5a. In addition switches |82y are controlled by arms or members |93 carried by and movable with the movable jaws or clamps 53 for the purpose to be more fully set forth hereinafter.

As shown in Fig. 5a, the sprocket wheel 44 is provided with a switch arm |84 projecting radiswitch |92, and further 'is connected by means of a wire. |93 with one terminal of one of the ,switches |82. The other terminal of the latter switch'rl82 is connected by means of a wire |94 with one terminal of :the other switch |82, which i eo in turn has its other terminal connected by means of'a wire |93EL with the power line |9| at a point beyond the manual switch |92.

The switch arm |84 also controls Va switch |94 which is connected by means of wires |95 with a conventional locking relay |96, the latter in turn being connected by wires |91 with a second switch |98 located as shown diagrammatically in Fig. 5. The relay |96 is further connected by means of a wire |99 with one wire 200 of a power line, and by means of a wire.20| witha wirev202 which leads to one terminal of each of the solenoids 12; vthe other terminal of eachof the latter is connected by means ofA wires 203 with the other wire200a of the last-mentioned power line.

The switch |98 is controlled by a switch arm 204 movable with` the index pin |30, said switch arm'204 further controlling a limit switch 205 and a limit switch 206 as it moves in opposite `directions vwith the index pin |30. The limit switch' 205 is connected by means of a wire 201 with one terminal of the solenoid |59, and by means of a wire 208 with one terminal of' the counter the other terminal of the latter is connected by means of a wire 209 with a wire 2|0 constituting part of a power line. The other terminal of the solenoid |59 isv connected by means of a wire 2|| with the other wire 2||la of said last named power line. f f

l'Ihelimit switch 206 is connected by a wire 2|2with the power wire 2|0 and by a wire 2|3 with one terminal of the solenoid |60, a wire 2|`4 leading from the other terminal of said solenoid |60 to the other power wire 2|||a to complete the circuit. The one side of the solenoid |58 is connected by a wire 2 5 with the power wire 2|0, and theother side of said solenoid |58 is connected by a wire 2|6 with one terminal of the counter |11. A wire 2|1 connects the other terminal of the counter ||1 with one terminal of one of the pressure operated switches |80, the other of which has its one terminal connected by means ofa wire 2|8 with a power line 2|9; the other terminals of the switches |80are connected with each other by a wire 220.

The product of the machine comprises two adjacent steel or other metallic bars A and B helically twisted together as illustrated in Fig. 4 in a predetermined helical pitch. When the twisting operation has 'been completed, the bars A and B because of inherent forces tend to untwist or uncoil; this untwisting or uncoiling of sa'id. twisted bars A and Bi will be transmitted to the twisting head or bushing 21 and accordingly will rotate the member 2| in a return direction on the rollers 20. Unless this tendency to uncoil is controlled, the possibility exists that the aforesaid operation of the member 2| in a return direction will bring the latter to rest in a rposition in which las the slot 26 and with it the recess or seat 30 is out of registry with the open slot |8 of the circular casing |1 with the result that adjustments of the mechanism would have to be eifected before the twisted bars A and B could be removed from the machine in the intended manner, and before another cycleof operation could be started on a successive `pair of bars A and B. To avoid this possibility and to definitely restore the twisting mechanism to an accurate starting position, 4at theend of each twisting operation, the uncoiling or untwisting tendency of the twisted bars A and B is deiinitely controlled inthe novel machinefbyrecoiling 4the twisted bars A and B under definite control and toa predetermined extent; at the same timethe aforesaid controlled recoiling of the twisted bars A and B will neutralize the inherent `forces developed therein during the twisting operations finished product. To accomplish these results the counter |15 is set to operate as an electric circuit controller when the in the twisting of the bars A and B has been reached, and the counter |11 has been set to similarly act as a circuit controller when the extent of vrecoil has been effected.

When the machine is at rest, the parts occupy the positions illustrated in Figs. 2 and 3,' and diagrammatically in Figs. 5 and 5a. At this stage, the carriers or troughs 32 are located in the outer position shown in Figs. 2 and 3 and the movable jaws'or clamps 53 are in theraised inoperative position illustrated Ain Fig.A 5a. It will be underand will produce a .uniform predetermined point stood that the motors 10 and pumps 69 are conn stantly in operation when the machine is in use so thatA pressure is provided inthe cylinders 59 for maintaining the pistons 58 and consequently the jaws or clamps 53 in the raised inoperative position.

When it is desired to begin an operativeA period of the machinegftwo-bars A and B are laid alongside of each other' in the troughs or carriers 32, with intermediate portions of said bars spanning the spacebetween opposed ends of said troughs or carriers 32, and opposite end portions of said bars A and'B projecting beyond the outer ends thereof. -When this has been done, the manual switch |92 is actuated to operate the starting box or locking relay |89 'in `a manner to start the motor 50 to, thereby transmit power to the crank 48 and connecting lrod 45 whereby the sprocket wheel 44 is rocked onits axis. Through the medium of thev sprocket vchain v43 this rotative rocking movement is vtransmitted to the sprocket wheel 42 and the shaft 40 and through the latter to the several sprocket 'wheels .39 carried by said shaft This causes a corresponding actuation of the sprocket chains 31 and associated sprocket wheels 38, the operation being such that the upper runs'of the chains`31move toward the right in Fig. 2, which corresponds to a movement toward the left in Fig.-3. In 'any case, said' upper runs ofthe chains 31 in the aforesaid movements carry along the troughs or carriers 32 and causethe latter to travel inwardly on the rollers 33 along thevtracks 35. At -this stage the parts occupy the position-shown inA Fig.`2 in which the slot V25 is horizontally disposed with its open end facing outwardly in registry with the open slot |8 of the circular casing |1`. -The previously mentioned inward movements of the carriers 32 accordingly transfer the` intermediate portions of the bars A and B into and lengthwise of said slot 26 and into the'recess or seat 30 of the twisting head or bushing 21 as shown'by dotted lines in Fig. 2. At the same time, the opposite outer end portions of said bars A and B are carried over and into the lower xed clamps or jaws .5| asl illustrated in Fig. 5a.

As the sprocket wheel 44 is rocked on its axis, the switch arm |84 will be shifted away from the limit switch |85 and into engagement with the limit switch |86 to thereby unlock the locking relay or starting box |89 and stop the motor 58; the carriers 32 accordingly remain or rest in the inner position with the intermediate portions of the bars A and B located in the seat 35 of the twisting head 21.

At the same time, the switch arm |84 will engage the locking relay |94 and bring about an energization and locking of said locking relay 94 which in turn energizes and locks the locking relay |98 to close the circuits which include the two solenoids 12 causing the latter to shift the valves in the cylinders S6. The operation of said valves is such that the pipes 63 are connected with the pipes 68 and consequently with the pumps 50; as a result pressure is exerted upon the pistons 58 which are forced downwardly in the cylinders 59 and thereby shift the jaws 53 downwardly to securely clamp the opposite end portions of the bars A and B between the jaws 53 and 5|. Because of the transversely curved active surfaces of the clamping blocks 5|a and 53a, the bars A and B will be forced toward each other and accordingly will be clamped together in close lengthwise engagement; at the same time, the teeth 5ib and 53b of said blocks 5|a and 53a will bite into said Abars A and B and securely hold them against lengthwise movement.

At the same time, the pressure developed by the pumps 89 to operate the clamping jaws 53 is effective through the pipes |8| on the pressure operated switches |80 to close the circuit which includes the solenoid |58; this circuit also includes the counterv |11 which is so arranged that at this point in said circuit, the latter is normally closed. As a result of the energization of the solenoid |58, the connected Valves |53 and |54 in the valve casing |31 are drawn downwardly against the tension of the spring |51 to connect the port |33 through the chamber |43 with the port |4|. At this stage the pipe |35 is accordingly connected with the pipes |42, ||0 and the auxiliary pump which is being operated by the motor 88. Pressure will therefore be effective in the left hand end of the cylinder |33 on the piston |32 whereby the latter will be shifted to the right in said cylinder |33 in Fig. 5. By this operation of the piston |32 the stem 3| will be correspondingly shifted to the right and the index pin |38 will be Withdrawn from the opening or recess l 29 in the index disc |28 thereby unlocking or releasing the latter. v

As these operations take place, the switch arm 204 will likewise be moved to the right in Fig. 5 away from the switch |98 and limit switch 205. As the arm 204 leaves the switch205, the circuit in which the latter `is located is closed by said switch 205; as this lcircuit also includes the counter |15 and is normally open thereat, the aforesaid movement of the yarm 204 away from the switch 205 has no operative effect and the tilting box 91 of the hydraulic pump 83 laccordingly remains in the set position shown in Fig. 5. As the movement to the right continues, the arm 204 wil1 engage the limit switch 205 and operate the same to closefthe circuit in which this switch 208 is located; it will be understood that the latter normally maintains its circuit in an open condition. As the last-mentioned circuit also'includes the solenoid |60, the latter will be energized when the switch 208 is operated; this causes the valve in the valve casing |22, which valve is similar to the one shown in Fig. 6,- to be actuatedin a manner 'to close the port |2| Hiand .|20 of `the relief valves 93 and 95.` This causes the hydraulic pump 83 to force oil or equivalent uid through the pipe 81 in the direction of the arrow ain Fig. 5 to the hydraulic motor 80, and back throughthe pipe 88V to the hydraulic pump 83 in the customary manner. The hydraulic motor 80 is thereby operatedto actuate the shaft181and pinion 13 whereby power is transmitted to the shaft 16 and pinion 15. The latter transmits power to the pinions 13 and 14 which in turn apply power to the toothed gear 23 whereby the annular `member 2| is caused to rotate on the rollers 20 and the twisting head 21 is correspondingly rotated on its axis.

As the opposite .end portions of the bars A and B are securely clamped in the jaws 53 and 5| at this stage, the rotation of said twisting head 21 by means of the recess or seat 30 will act on the intermediate portions of said barsA and B Ato helically twist the latter together in the manner illustrated in Fig. 4; due to the fact that the seat 30 of the twisting head 21 is effective at an inter'- mediate point of the bars A and B, the latter will be twisted together in opposite helices upon opposite sides of said twisting head 21. This twisting operation is continued for a predetermined period or until a predetermined number of twists for which the counter |15 is set have been eifected. At this point .said .counter |15 will act to close the circuit in which it is located and thereby will cause lthe solenoid .|59 yto be energized. The valve in the casing |04, which also is similar to the valve shown in Fig. 6 will thereby be shifted to open the port |09 to the port |08, and connect the pipe |05 with the pipe IH) and through the latter with the auxiliary pump at the same time the port |03 will be opened to the port |01 to connect the pipe |02 with the pipe |08 leading to the interior of the tank 8|. As aresult of these operations, oil or other suitable fluid under pressure will'be forced into the lower end of the cylinder |00 and will raisevthe plunger 99 therein; this movement will be transmitted by the link 98 to the tilting box 91 of the hydraulic pump 83 and swing said tilting box 91 upward against the stop |0| to the position indicated by the broken line b in Fig. 5. As this takes place, the oil or its equivalent above the plunger 58 will be forced from the cylinder |00 through thepipe |82, ports |03 and |81, and through the pipe 08 yback tothe tank 8|.

The circulation of oil or its equivalent will accordingly be reversed, so that said oil now flows through the pipe 88 in the direction of the arrow c in Fig. 5 and through the pipe 81 back to the hydraulic pump 83. The hydraulic motor 80 will thereby be reversed to correspondingly reverse the direction of operation of the shaft 19 and associated gearing, as `well as the toothed gear 23 and annular member 2|. As a result of'this, the twisting head 21 is also reversed and the seat 30 will ybecome effective on the intermediate portions of the twisted 'bars A and B in a correspondingly reverse direction to recoil or untwist said bars A and B. This recoling is continued for a predetermined period or until the slot 25 of the member 2| is in accurate registry with the open slot I8 of the circular casing I1 and until any inherent tendency in said bars to untwist is neutralized; the counter |11 is set to and the bleeder pipesy ingly willbe exerted become operative. at this point' to open its circuit and ythereby bring about a de-energization of the solenoid |50.

As. thisoccurs, the valve |53|54 will be shifted by its spring |51 back to its normal position in the casing |31 as .illustrated in Fig. 6; this will restore communicationbetween the ports |33 and |4| and will connect .the pipe |34 with the pipe |42 and through the pipe ||0 with the auxiliary pumpv Oil. or its equivalent will now ,be forced under pressure! into the right hand end of the cylinder |33 andwill force the piston` |32`to the left therein and cause the index pin |30 to bear against the face of the index disc |28 and to enterthe opening or recess |29 thereof when the latter and said pin are in registry with each other. Whenv this takes place, the switch arm 204 will engage and operate the limit switch 205 to open .its circuit and as the switch arm 294 moves away from 'the limit switch y206, the latter willy open its circuit and thereby derenergize the solenoid when index pin |30 enters the opening or recess |29 in the index disc |29, the switch arm 204;will engage'and operate the limit switchz 205 to open its circuit and thereby de-'energize thesolenoid` |59. As the solenoid |30 ,isr de-energized as mentioned above, the valve in the casing |22 Ywill open the pipes ||9 and |25 ofthe relief valves 93 and 95, while the de-energization vofv the solenoid |59 will shift the valve in the casing l|04 in a manner to connect the. upper end of the cylinder |00, throughthe pipe |02, ports |03 .and |04, andv pipe ||0 with theauxiliary pump .'Pressure accordon the'plunger 99 to force the same downwardly7 in the cylinder |00 and thereby restore the tilting boX 91 of the hydraulic pump 83 to the position shown in Fig. 5.

As theswitch arm 204 .operates the switch 205 to bring about the aforesaid. operations, said arm 204 at the sameV time engages. and operates the switch |98 'to unlock thelocking relay |96 and thereby break the circuit in which the solenoids 12 are located. The latter are accordingly deenergized whereuponthe valves in the cylinders 66 are operatedto connect the lower ends of the cylinders 59 through thepipes 62 and 68 with the pumps 69. Thepistons 56 are thereby raised and the jaws 53 are lifted to the inoperative positions shown in Fig..5a toA release the opposite end portions of the twisted bars A and B. It will be understood that de-energization of the solenoids |59, |60 and 12 takes place at approximately the same time, so that the" operations described Vabove are performed more or less simultaneously. v-

In the raised position of the jaws 53, the arms or members |83 carried thereby' engage and operate the switches .|82 to close the circuit in which the latter are located in .series and thereby operate the locking relay |89 in a manner to start the motor 50. The latter will rock the gear ,"84 in a return direction and correspondingly operate .theassociated parts whereby the carriers 32 with the .twisted bars A and B carried thereby are shifted outwardly to the position shown in Figs; 2, 3 and 5a. in which position the twisted bars Aand B are easily removable from the machine. As the gear .84 is thus rocked in the return direction, the switch arm |84 will engage and operate the. vlimit switch |85 to break all circuits and complete thefoperative cycle. The twisted bars A and B maynow be removed from the carriers 32 andv replaced byother bars after which the .described cycleof operations may be repeated. Y 1 Y 4It will be noted that .the toothedperiphery of the gear 23 is interrupted by the 'open entrance end of the slot 26. .To avoidthe lpossibility that this interruption may. interfere ,Withthe operation of the twisting operations of the; machine, the two pinions 13 and. 14 are provided upon opposite sides of a horizontal line passing through the axis of said gear .23. As the slot 26, in transversing its rotative path during said twisting operations, reachesone of said gears 13 or 14, the othergear, either 13 or 14 will be positively in mesh with the gear 23; the latter is thus subjected to a continuous application of rotative power so that the aforesaid twisting operations are carried out uniformly and without f interruption. y

The machine is relatively simple in construction and of maximum efficiency, and enables the bars A and B to be handledfwith a minimum of effort and without difficulty, before and after the twisting thereof has been accomplished. The machine enables the bars A and B to betwisted cold in helices of any predetermined pitch, and by the controlled recoiling of the twisted bars neutralizes any inherent tendency therein to uncoil and therby definitely insures a uniform product of the desired type. Because of the fact that the bars A and B are securely clamped during the twisting operation, saidy bars as a result of the helical twisting thereof will be stretched or elongated; this brings about a material increase in the yield point of the twisted bars which is of maximum importance in reinforced concrete work. At the Sametime, as previously stated herein, the recoiling operation is so controlled that it also definitely and positively restores the annular member 2| toits initial position of rest in which the recess or seat 30 and with it the slot 26 is accurately-in registry with the open slot I8 of the circular casing |1. In other Words, the twisting mechanism is definitely adjusted to a position in which the twisted bars A and B may be readily shifted for removal from the machine; at the same time the twisting mechanism is set in position for the beginning of another cycle of operations on succeeding bars A and B.

The twisted bars are designed primarily for use as concrete re-inforcements although they are not limited to such use, Vnor is,v the machine restricted to the productionof such reinforcement bars.

Various changes in the specific forms shown and described may be made within the scope of` the claims without departing from the spirit of the invention. f y

Iclaim: N I v 1. In a machine for twisting bars as described, a base, a circular casing mounted on said base and'v provided with eccentrically located openings in its opposite Walls, and having a radial slot open at the outer periphery of said casing and at said openings, a plurality of rollers arranged in opposed groups about'said openings and rotat ably mounted on said oppositeY Walls of said casing, an annular member rotatably supported on said rollers, webs extending inwardly and outwardly respectively from said annular member, a toothed gear carried by said outwardly extending web, a hub carriedby said inwardlyl extending web in eccentric relation to said annular member, said annular member and webs having a radial slot extending from the periphery of the toothed gear to the bore of said hub, a. twisting head mounted in said hub and having a twisting seat A f ing head at its axis in open communication with said radial slot, clamping means located in spaced relation to said casing upon opposite sides thereof, a pair of movable carriers located in spaced, longitudinal alignment and extending in opposite directions upon opposite sides of said casing and terminating at their outer ends adjacent to said clamping means, the bars to be twisted being supported by said carriers and having intermediate portions bridging the space between opposed inner ends thereof, and having outer end portions projecting outwardly beyond the outer ends of said carriers, rollers supporting said carrier, stationary tracks for said rollers, means for moving said carriers on said tracks whereby said intermediate portions of said bars are moved lengthwise of said radial slot into said twisting seat, and the opposite end portions are shifted into operative relation to said clamping means, means for operating said clamping means to clamp said opposite end portions of said bars against movement, means operatively connected with said toothed gear for operating said twisting head to thereby helically twist said bars together, means for automatically arresting the twisting operation at a predetermined point and reversing the operation of said twisting head to recoil the twisted bars to a predetermined extent, and means for arresting the operation of said twistand operating said clamping means to release said twisted bars and for shifting said carriers to their initial position to permit removal of said twisted bars.

2. In a machine for twisting bars as described, a base, a circular casingfmounted on said base and provided with eccentrically located openings its opposite walls, and having a radial slot open at the outer periphery of said casing and at said openings. a plurality of rollers arranged in opposed groups about said openings and rotatably mounted on said opposite Walls of said casing, an annular member rotatably supported on said rollers, webs extending inwardly and outwardly respectively from said annular member, a toothed gear carried by said outwardly extending web, a hub carried by said inwardly extending web in eccentric relation to said annular member, said annular member and webs having a radial slot extending from the periphery of the toothed gear to the bore of said hub, a twisting head mounted in said hub and having a twisting seat at its axis in open communication with said radial slot, clamping means located in spaced relation to said casingr upon opposite sides thereof, a pair of movable carriers located in spaced, longitudinal alignment and extending in opposite directions upon opposite sides of said casing and terminating at their outer ends adjacent to said clamping means, the bars to be twisted being supported by said carriers and having intermediate portions bridging the space between opposed inner ends thereof, and having outer end portions projecting outwardly beyond the outer ends of said carriers, rollers supporting said carriers, stationary tracks for said rollers, means for moving said carriers on said tracks whereby said intermediate portions of said bars are moved lengthwise of said radial slot into said twisting seat, and the opposite end portions are shifted into operative relation to said clamping means, means for operating said clamping means to clamp said o-pposite end portions of said bars against movement, means operatively connected with said toothed gear for operating said twisting head to thereby helically twist said bars together, and means for reversing th'e operation of said twisting head to recoil they twisted bars to a predetermined extent.

3. In a machine for twisting bars as described, a base, a circular casing mounted on said base and provided with eccentrically located openings in its opposite walls, and having a radial slot open at the outer periphery of said casing and at said openings, a plurality of rollers arranged in opposed groups about said openings and rotatably mounted on said opposite walls of said casing, an annular member rotatably supported on said rollers, webs extending inwardly and outwardly respectively from sai-d annular member, a toothed gear carried by said outwardly extending web, a hub carried by said inwardly extending web in eccentric relation tov said annular member, said annular member and webs having a radial slot extending from the periphery of the toothed gear to the bore of said hub, a twisting head mounted in said hub and having a twisting seat at its axis in Iopen communication with said radial slot, clamping means located in spaced relation to said casing upon opposite sides thereof, a pair of movable carriers located in spaced, longitudinal alignment and extending in opposite directions upon opposite sides of said casing and terminating at their outer ends adjacent to said clamping means, the bars to be twisted being supported by said carriers and having intermediate portions bridging the space between opposed inner ends thereof, and having outer end portions projecting outwardly beyond the outer ends of said carriers, rollers supporting said carriers, stationary tracks for said rollers, means for moving said carriers on said tracks whereby said intermediate portions of said bars are moved lengthwise of said radial slot into said twisting seat, and the opposite end portions are shifted into operative relation to said clamping means, means for operating said clamping means to clamp said opposite end portions of twist said bars together.

4. In a twisting machine of the kind described, a twisting head, clamping means in spaced relation to said twisting head upon opposite sides thereof, carrying means normally occupying a receiving position for receiving the bars to be twisted and for c-onveying the latter from said receiving position to shift intermediate portions of said bars into operative connection with said twisting head and to coincidentally shift opposite endy portions of said bars into operative relation with said clamping means, means for operating said clamping means to clamp said opposite end portions of said bars against movement, and means for operating said twisting head to develop twisting forces at said intermediate por-- tions of said bars gether.

5. In a twisting machine of the kind described,

to helically twist said bars toa twisting head, clamping means in `spaced rela' tion to said twisting head upon opposite sides thereof, carrying means normally occupyingal receiving position for receiving the bars to be twisted and for conveying the latter from said receiving position to shift intermediate portions of said bars into operative connection with said twisting head and to coincidentally shift opposite end portions of said bars into operative relation with said clamping means, means for operating said clamping means to clamp said opposite end portions of said bars against movement, means for operating said twisting head to develop twist Fil lao

l oz

8. ing forces at Vsaid intermediate portions of said bars to helically twist said barsv together, and

means for reversing the operation of said twistof the bars into said twisting seat, and opposite end portions of said bars into operative relation with said clamping means, means for operating the latter to clamp said opposite end portions of said bars against movement, means for operating said twisting head to helically twist said bars together, means for reversing the operation of said twisting head at a predetermined point in the twisting operation to recoil the twisted bars to a predetermined extent, and means operative at the end of said recoiling operation to arrest the operation of the twisting head, to operate the clamping Vmeans to release the twisted bars, and to operate the conveying means in a return direction to thereby shift the twisted bars away from the twisting head and clamping means for removal from the machine.

'7. In a machine for twisting bars as described, a twisting head having an open twisting seat, clampingmeans located in spaced relation to said twisting head upon opposite sides thereof, conveying means for shifting intermediate portions of said bars into said twisting seat, and opposite end portions of said bars into operative relation with said clamping means, a hydraulic transmission, gearing connecting said transmission with said twisting head, an index disc operatively connected with said gearing, an index pin for locking said index disc and said gearing against operation, electrically controlled means for shifting said index pin to release said index disc and gearing, electrically controlled means set in motion as said index pin is shifted to its releasing position whereby said hydraulic transmission is actuated to operate said twisting head to helically twist said bars together, a counter, electrically controlled means controlled by said counter whereby said hydraulic transmission is reversed to reverse the operation of said twisting head whereby said twisted bars are recoiled, a second counter whereby the electrically controlled means is de-energized to shift said index pin into locking engagement with said index disc to thereby lock the latter and said gearing, electrically controlled means i controlled by said index pin in its locking position to bring about an operation of said clamping means to release the opposite end portions of the twisted bars and an operation of said conveying means to shift said twisted bars out of said twisting seat and away from said clamping means for removal from the machine, and switching means effective when said conveying means has completed the last named shifting of the twisted bars to arrest the operation of all parts of said machine.

8. In a machine for twisting bars as described, a twisting head having an operi twisting seat, clamping means located in spaced relation to said twisting head upon opposite sides thereof, conveying means for shifting intermediate portions of said bars into said twisting seat, and opposite end portions of said bars into operative relation with said clamping means, a hydraulic transmission, gearing connecting said transmission with said twisting head, locking means for locking said gearing against operation, electrically controlled means for operating said locking means to release said gearing and for starting said hydraulic transmission to operate said twisting head to thereby helically twist said bars together, electrically controlled means for reversing V`the hydraulic transmission to correspondingly 'reverse the `operation of said twisting head to thereby'recoil saidgtwisted bars to a predetermined extent, and for operating the locking means'to re-lock said gearing against operation, electrically controlled means for operating said clamping` means to release said opposite end portions of the twisted bars and for operating said conveyingV means to shift said twisted bars out of said twisting seat and awayffrom said clamping means for removal fromthe machine, and switching'means effective whenY said conveying means-has completed the last named shifting of the twisted bars to arrest thevoperation of all parts of the machine.

- 9. Ina machine for twisting bars as described, twisting mechanism, clamping means located in operative relation tol said twisting mechanism, conveying meansfor shifting said bars into operative relation with said twisting mechanism and said clamping means, means for operating the latter to clamp predetermined portions of said bars against movement and for subsequently releasing said clamping means, a hydraulic transmission for operating said twisting mechanism in one direction to helically twist said bars together and subsequently in a reverse direction to recoil said twisted bars to a predetermined extent', -and means for automatically controlling the operation of said hydraulic transmission, and the operationfof said conveying means whereby the twisted and recoiled bars are moved out of operative relation with said twisting mechanism and clamping means fork removal from the machine; f l

`10. In a machine for twisting bars as described, twisting mechanism, clamping means located in operative relation-'to rsaid twisting mechanism, means for supporting said bars in operative relation with'said twisting mechanism and 'said clamping means, means'for operating the latter to Aclamp predetermined portions of said bars against movement and for subsequently releasing said clamping means, and a hydraulic transmission for 4operating said twisting mechanism to helically twist said bars together and to subsequently recoil said twisted'bars to a predetermined extent;

' l1; In' a machine for twisting barsas described, twisting 'mechanism, means for supporting two bars in operative relation to said twisting mechanism during the twisting operation, and clamping jaws for,l clampingv predetermined portions of said bars against movement during said twisting operation, the active clamping surfaces of said jaws being concave whereby said bars are forced into -close lengthwise 'engagement with each other on said supporting means and clamped'. v

12. In a machine for twisting bars as described, twisting mechanism, means for supporting two bars in operative relation to said twisting mechanism during the twisting operation, clamping jaws for clamping predetermined portions of said bars against movement during said twisting operation, and clamping blocks countersunk in the opposed faces of said jaws, the active surfaces of i said clamping blocks being transversely curved and provided with grooves extending in the direction of the curves whereby said bars are forced into close lengthwise engagement with each other on said supporting means and clamped.

13. In a machine for twisting bars as described, means for clamping predetermined portions of the bars to be twisted, against movement, twisting means for helically twisting said bars together to a predetermined extent, and means for reversing the operation of said twisting means to a controlled extent subsequent to the twisting operation to restore the latter to its initial starting position independently of any uncoiling tendencies inherent in the twisted bars.

14. In a twisting machine of the kind described, a twisting head, clamping means in spaced relation to said twisting head upon opposite sides thereof, carrying means normally occupying a receiving position for receiving the bars to be twisted and for conveying the latter from said receiving position to shift intermediate portions of said bars into operative connection with said twisting head and to coincidentally shift opposite `end portions of said bars into operative relation with said clamping means, means for operating said clamping means to clamp said opposite end portions of said bars against movement, means having an operative period of predetermined length for operating said twisting head to develop twisting forces at said intermediate portions of said bars during said operative period whereby said bars are helically twisted together to provide a predetermined number of twists, and means effective at the end of said operative time period for reversing the operation of said twisting head to restore the latter to its initial starting position and to coincidentally recoil said twisted bars to thereby neutralize uncoiling tendencies inhe-rent in the twisted bars.

15. In a machine for twisting bars as described, clamping means for developing clamping forces on two adjacent bars, twisting means for helically twisting said bars together, a hydraulic transmission including a hydraulic pump and a hydraulic motor operatively connected with said twisting means, and means for controlling the operation of said hydraulic transmission to cause said hydraulic pump and motor to operate said twisting means in one direction for a predetermined time period and in a reverse direction for a subsequent predetermined time period.

16. In a machine for twisting bars as described, clamping means for clamping two adjacent bars against movement, twisting mechanism for helically twisting said bars together, a hydraulic transmission including a hydraulic motor operatively connected with said twisting mechanism, a hydraulic pump for operating said hydraulic motor, and an adjustable control for controlling the operation of said hydraulic pump, electro-magnetic controlled means for actuating said hydraulic transmission to operate said twisting mechanism to helically twist said bars together, electro-magnetic controlled means whereby the operation of said twisting mechanism is arrested after a predetermined number of helical twists have been effected, electro-magnetic controlled means for shifting the adjustable control of said hydraulic pump to reverse the operation of said hydraulic motor and the twisting mechanism whereby said twisted bars are recoiled to a predetermined extent, and means operative at the end of said recoiling operation to arrest the reverse operation of said twisting mechanism, and to operate said clamping means to release the twisted bars.

17. In a machine for producing helically twisted bars of the kind described, twisting mechanism including a rotatable twisting member provided with a slot riphery of said member to substantiallythe center thereof, means for conveying the stock to be twisted into the slot of said twisting member, clamping means for holding the stock againstA rotative as well as axial movements during the twisting operation, means for driving said twisting mechanism, and control means for controlling said driving means in a manner to subject said stock to a predetermined number of helical twists in one direction and recoils in the reverse direction.

18. In a machine for o1 the kind described, twisting mechanism including a gear provided with a slotextending from tially the center thereof, means for inserting thev stock to be twisted into the slot of said twisting gear, clamping means for holding said stock against rotative as well as axial movements during the twisting operation, means for driving said twisting mechanism, control elements for controlling said driving means in a manner to subject said stock to -a predetermined number of recoilsin the reversed direction, and additional means for releasing said clamping means subsequent to said predetermined number of recoils.

19. In a machine for producing twistedbars ,ofl

the kind described, twisting mechanism for twisting the stock, constant horse power driving means for rotating said twisting mechanism at decreasing speeds during the twisting process, the decrease in twisting speed being proportion-- ate to the increase in required twisting torque, and control means for adjusting the magnitude of the constant horse power output of said driving means dependent on the desired range of twisting speeds during the twisting process, to obtain predetermined physical properties in the twisted bars.

20. In amachine for producing twisted bars of the kind described, in combination with a twisting mechanism for twisting the stock and clamping means for holding said stock against rotative and axial movements, driving means for rotating said twisting mechanism at varying speeds during the twisting process, and control means for adjusting the constant horse power output of said driving means in dependence upon the desired final physical properties of the twisted bars.

21. In a machine for producing twisted bars of the kind described, in combination with a twisting mechanism for twisting thev stock, constant horse power driving means for actuating said twisting mechanism, controls for said driving means to automatically decrease the twisting speed as the twisting process progresses, the decrease in twisting speed being proportionate to the increase in twisting torque required, and aum'liary control means for pre-setting the magnitude of the constant horse power output in dependence upon the desired iinal strength of the twisted bars.

22. In a machine for producing twisted bars of the kind described, clamping means for holding the stock against rotative and axial movements, a twisting mechanism located at an intermediate point of said stock, driving means opextending from the peproducing twisted barsv the circumference of the gear to substan.

, of twists in one direction and to a predetermined number of recoils in the opposite direction, and i an indexing mechanism for arresting said twistcycle.

151 of. the kind described,

ing mechanism in a predetermined angular position after the recoiling operation to facilitate loading of the machine for subsequent twisting.

In a machine lfor producing twisted bars e clamping. means for holding predetermined sections of the stock to be twisted against rotative and axial movements, an intermittently rotatable twisting head located between said clamping means, a gear carrying said twisting head at its centre and provided with a relatively wide slot extending from the periphery of said gear into communication with said twisting head, for feeding the stock to be twisted into the twisting head, the latter having a relatively narrow recess connected with the inner end of said wide slot for locating said stock against relative movement relatively to the twisting head, driving means operatively connected with said gear, control means for controlling said driving means in a manner to subject said stock to a predetermined number of helical twists in one, direction and to limit the number of recoils of the twisted stock in the reverse direction, and indexing means for locating said twisting head in a predetermined angular position subsequently to the recoiling operation.

24. In a machine for producing twisted bars of the kind described,y clamping means for developing clamping forces on two adjacent bars, twisting means for helically twisting said bars, a hydraulic transmission including a. variable displacement pump and a variable displacement motor operatively connected with said twisting l means, and means for contro-lling the operation of said hydraulic pump in a ma -ner to give high volume delivery for twisting said bars in one direction and to give low volume delivery in opposite direction for controlling the recoil of said twisted bars.

25. In a machine for producing twisted bars of the kind described, clamping means'for holding the ends of two adjacent bars, twisting means for helicallyv twisting said bars together, driving means for operating said twisting means, and

means for controlling the operation of said driving means in a manner to obtain a predetermined number of twists in one direction, and. to obtain subsequently a predetermined number of recoils in the reverse direction.

26. In a machine. for producing twisted bars of the kind described., clamping means for holding the ends of two'adjacen-.t bars., twisting means for helically twisting. said. barstogether, driving means for operating said twisting means, and means for controlling the. operation of said driving means to obtain. a predetermined number of twists in one direction, and to obtainA subsequently a predeterminedv number of recoils in the reverse direction, and employing vthe driving means for etfecting a slowrecoil speed.

ODD WENNBERG. 

